Mount St. Helens. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome.ount St. Helens. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome.
Definition of plantar. : of or relating to the sole of the foot plantar wart.
C18: from Latin plantÄris, from planta sole of the foot. Word Origin and History for plantar Expand. adj. 1706, from Latin plantaris pertaining to the sole of the foot, from planta sole of the foot (see plant (n.)).